filtrctx.c File Reference

#include <ntoskrnl.h>
#include <debug.h>

Include dependency graph for filtrctx.c:

Go to the source code of this file.

Classes
struct	_FILE_OBJECT_FILTER_CONTEXTS

Macros
#define	NDEBUG

Typedefs
typedef struct _FILE_OBJECT_FILTER_CONTEXTS	FILE_OBJECT_FILTER_CONTEXTS
typedef struct _FILE_OBJECT_FILTER_CONTEXTS *	PFILE_OBJECT_FILTER_CONTEXTS

Functions
VOID NTAPI	FsRtlPTeardownPerFileObjectContexts (IN PFILE_OBJECT FileObject)
LOGICAL NTAPI	FsRtlIsPagingFile (IN PFILE_OBJECT FileObject)
PFSRTL_PER_FILEOBJECT_CONTEXT NTAPI	FsRtlLookupPerFileObjectContext (IN PFILE_OBJECT FileObject, IN PVOID OwnerId OPTIONAL, IN PVOID InstanceId OPTIONAL)
PFSRTL_PER_STREAM_CONTEXT NTAPI	FsRtlLookupPerStreamContextInternal (IN PFSRTL_ADVANCED_FCB_HEADER AdvFcbHeader, IN PVOID OwnerId OPTIONAL, IN PVOID InstanceId OPTIONAL)
NTSTATUS NTAPI	FsRtlInsertPerFileObjectContext (IN PFILE_OBJECT FileObject, IN PFSRTL_PER_FILEOBJECT_CONTEXT Ptr)
NTSTATUS NTAPI	FsRtlInsertPerStreamContext (IN PFSRTL_ADVANCED_FCB_HEADER AdvFcbHeader, IN PFSRTL_PER_STREAM_CONTEXT PerStreamContext)
PFSRTL_PER_FILEOBJECT_CONTEXT NTAPI	FsRtlRemovePerFileObjectContext (IN PFILE_OBJECT FileObject, IN PVOID OwnerId OPTIONAL, IN PVOID InstanceId OPTIONAL)
PFSRTL_PER_STREAM_CONTEXT NTAPI	FsRtlRemovePerStreamContext (IN PFSRTL_ADVANCED_FCB_HEADER AdvFcbHeader, IN PVOID OwnerId OPTIONAL, IN PVOID InstanceId OPTIONAL)
VOID NTAPI	FsRtlTeardownPerStreamContexts (IN PFSRTL_ADVANCED_FCB_HEADER AdvFcbHeader)

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 12 of file filtrctx.c.

Typedef Documentation

FILE_OBJECT_FILTER_CONTEXTS

typedef struct _FILE_OBJECT_FILTER_CONTEXTS FILE_OBJECT_FILTER_CONTEXTS

PFILE_OBJECT_FILTER_CONTEXTS

typedef struct _FILE_OBJECT_FILTER_CONTEXTS * PFILE_OBJECT_FILTER_CONTEXTS

Function Documentation

FsRtlInsertPerFileObjectContext()

NTSTATUS NTAPI FsRtlInsertPerFileObjectContext	(	IN PFILE_OBJECT	FileObject,
		IN PFSRTL_PER_FILEOBJECT_CONTEXT	Ptr
	)

Definition at line 175 of file filtrctx.c.

{
    PFILE_OBJECT_FILTER_CONTEXTS FOContext = NULL;

    if (!FileObject)
    {
        return STATUS_INVALID_PARAMETER;
    }

    if (!(FileObject->Flags & FO_FILE_OBJECT_HAS_EXTENSION))
    {
        return STATUS_INVALID_DEVICE_REQUEST;
    }

    /* Get filter contexts */
    FOContext = IoGetFileObjectFilterContext(FileObject);
    if (!FOContext)
    {
        /* If there's none, allocate new structure */
        FOContext = ExAllocatePoolWithTag(NonPagedPool, sizeof(FILE_OBJECT_FILTER_CONTEXTS), 'FOCX');
        if (!FOContext)
        {
            return STATUS_INSUFFICIENT_RESOURCES;
        }

        /* Initialize it */
        ExInitializeFastMutex(&(FOContext->FilterContextsMutex));
        InitializeListHead(&(FOContext->FilterContexts));

        /* Set it */
        if (!IoChangeFileObjectFilterContext(FileObject, FOContext, TRUE))
        {
            /* If it fails, it means that someone else has set it in the meanwhile */
            ExFreePoolWithTag(FOContext, 'FOCX');

            /* So, we can get it */
            FOContext = IoGetFileObjectFilterContext(FileObject);
            if (!FOContext)
            {
                /* If we fall down here, something went very bad. This shouldn't happen */
                ASSERT(FALSE);
                return STATUS_UNSUCCESSFUL;
            }
        }
    }

    /* Finally, insert */
    ExAcquireFastMutex(&(FOContext->FilterContextsMutex));
    InsertHeadList(&(FOContext->FilterContexts), &(Ptr->Links));
    ExReleaseFastMutex(&(FOContext->FilterContextsMutex));

    return STATUS_SUCCESS;
}

FsRtlInsertPerStreamContext()

NTSTATUS NTAPI FsRtlInsertPerStreamContext	(	IN PFSRTL_ADVANCED_FCB_HEADER	AdvFcbHeader,
		IN PFSRTL_PER_STREAM_CONTEXT	PerStreamContext
	)

Definition at line 235 of file filtrctx.c.

{
    if (!(AdvFcbHeader) || !(AdvFcbHeader->Flags2 & FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS))
    {
        return STATUS_INVALID_DEVICE_REQUEST;
    }

    ExAcquireFastMutex(AdvFcbHeader->FastMutex);
    InsertHeadList(&(AdvFcbHeader->FilterContexts), &(PerStreamContext->Links));
    ExReleaseFastMutex(AdvFcbHeader->FastMutex);
    return STATUS_SUCCESS;
}

FsRtlIsPagingFile()

LOGICAL NTAPI FsRtlIsPagingFile

(

IN PFILE_OBJECT

FileObject

)

Definition at line 64 of file filtrctx.c.

{
    return MmIsFileObjectAPagingFile(FileObject);
}

FsRtlLookupPerFileObjectContext()

PFSRTL_PER_FILEOBJECT_CONTEXT NTAPI FsRtlLookupPerFileObjectContext	(	IN PFILE_OBJECT	FileObject,
		IN PVOID OwnerId	OPTIONAL,
		IN PVOID InstanceId	OPTIONAL
	)

Definition at line 74 of file filtrctx.c.

{
    PLIST_ENTRY NextEntry;
    PFILE_OBJECT_FILTER_CONTEXTS FOContext = NULL;
    PFSRTL_PER_FILEOBJECT_CONTEXT TmpPerFOContext, PerFOContext = NULL;

    if (!FileObject || !(FOContext = IoGetFileObjectFilterContext(FileObject)))
    {
        return NULL;
    }

    ExAcquireFastMutex(&(FOContext->FilterContextsMutex));

    /* If list is empty, no need to browse it */
    if (!IsListEmpty(&(FOContext->FilterContexts)))
    {
        for (NextEntry = FOContext->FilterContexts.Flink;
             NextEntry != &(FOContext->FilterContexts);
             NextEntry = NextEntry->Flink)
        {
            /* If we don't have any criteria for search, first entry will be enough */
            if (!OwnerId && !InstanceId)
            {
                PerFOContext = (PFSRTL_PER_FILEOBJECT_CONTEXT)NextEntry;
                break;
            }
            /* Else, we've to find something that matches with the parameters. */
            else
            {
                TmpPerFOContext = CONTAINING_RECORD(NextEntry, FSRTL_PER_FILEOBJECT_CONTEXT, Links);
                if ((InstanceId && TmpPerFOContext->InstanceId == InstanceId && TmpPerFOContext->OwnerId == OwnerId) ||
                    (OwnerId && TmpPerFOContext->OwnerId == OwnerId))
                {
                    PerFOContext = TmpPerFOContext;
                    break;
                }
            }
        }
    }

    ExReleaseFastMutex(&(FOContext->FilterContextsMutex));

    return PerFOContext;
}

FsRtlLookupPerStreamContextInternal()

PFSRTL_PER_STREAM_CONTEXT NTAPI FsRtlLookupPerStreamContextInternal	(	IN PFSRTL_ADVANCED_FCB_HEADER	AdvFcbHeader,
		IN PVOID OwnerId	OPTIONAL,
		IN PVOID InstanceId	OPTIONAL
	)

Definition at line 126 of file filtrctx.c.

{
    PLIST_ENTRY NextEntry;
    PFSRTL_PER_STREAM_CONTEXT TmpPerStreamContext, PerStreamContext = NULL;

    ASSERT(AdvFcbHeader);
    ASSERT(FlagOn(AdvFcbHeader->Flags2, FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS));

    ExAcquireFastMutex(AdvFcbHeader->FastMutex);

    /* If list is empty, no need to browse it */
    if (!IsListEmpty(&(AdvFcbHeader->FilterContexts)))
    {
        for (NextEntry = AdvFcbHeader->FilterContexts.Flink;
             NextEntry != &(AdvFcbHeader->FilterContexts);
             NextEntry = NextEntry->Flink)
        {
            /* If we don't have any criteria for search, first entry will be enough */
            if (!OwnerId && !InstanceId)
            {
                PerStreamContext = (PFSRTL_PER_STREAM_CONTEXT)NextEntry;
                break;
            }
            /* Else, we've to find something that matches with the parameters. */
            else
            {
                TmpPerStreamContext = CONTAINING_RECORD(NextEntry, FSRTL_PER_STREAM_CONTEXT, Links);
                if ((InstanceId && TmpPerStreamContext->InstanceId == InstanceId && TmpPerStreamContext->OwnerId == OwnerId) ||
                    (OwnerId && TmpPerStreamContext->OwnerId == OwnerId))
                {
                    PerStreamContext = TmpPerStreamContext;
                    break;
                }
            }
        }
    }

    ExReleaseFastMutex(AdvFcbHeader->FastMutex);

    return PerStreamContext;
}

FsRtlPTeardownPerFileObjectContexts()

VOID NTAPI FsRtlPTeardownPerFileObjectContexts

(

IN PFILE_OBJECT

FileObject

)

Definition at line 28 of file filtrctx.c.

{
    PFILE_OBJECT_FILTER_CONTEXTS FOContext = NULL;

    ASSERT(FileObject);

    if (!(FOContext = IoGetFileObjectFilterContext(FileObject)))
    {
        return;
    }

    ASSERT(IoChangeFileObjectFilterContext(FileObject, FOContext, FALSE) == STATUS_SUCCESS);
    ASSERT(IsListEmpty(&(FOContext->FilterContexts)));

    ExFreePoolWithTag(FOContext, 'FOCX');
}

Referenced by IopDeleteFile().

FsRtlRemovePerFileObjectContext()

PFSRTL_PER_FILEOBJECT_CONTEXT NTAPI FsRtlRemovePerFileObjectContext	(	IN PFILE_OBJECT	FileObject,
		IN PVOID OwnerId	OPTIONAL,
		IN PVOID InstanceId	OPTIONAL
	)

Definition at line 254 of file filtrctx.c.

{
    PLIST_ENTRY NextEntry;
    PFILE_OBJECT_FILTER_CONTEXTS FOContext = NULL;
    PFSRTL_PER_FILEOBJECT_CONTEXT TmpPerFOContext, PerFOContext = NULL;

    if (!FileObject || !(FOContext = IoGetFileObjectFilterContext(FileObject)))
    {
        return NULL;
    }

    ExAcquireFastMutex(&(FOContext->FilterContextsMutex));

    /* If list is empty, no need to browse it */
    if (!IsListEmpty(&(FOContext->FilterContexts)))
    {
        for (NextEntry = FOContext->FilterContexts.Flink;
             NextEntry != &(FOContext->FilterContexts);
             NextEntry = NextEntry->Flink)
        {
            /* If we don't have any criteria for search, first entry will be enough */
            if (!OwnerId && !InstanceId)
            {
                PerFOContext = (PFSRTL_PER_FILEOBJECT_CONTEXT)NextEntry;
                break;
            }
            /* Else, we've to find something that matches with the parameters. */
            else
            {
                TmpPerFOContext = CONTAINING_RECORD(NextEntry, FSRTL_PER_FILEOBJECT_CONTEXT, Links);
                if ((InstanceId && TmpPerFOContext->InstanceId == InstanceId && TmpPerFOContext->OwnerId == OwnerId) ||
                    (OwnerId && TmpPerFOContext->OwnerId == OwnerId))
                {
                    PerFOContext = TmpPerFOContext;
                    break;
                }
            }
        }

        /* Finally remove entry from list */
        if (PerFOContext)
        {
            RemoveEntryList(&(PerFOContext->Links));
        }
    }

    ExReleaseFastMutex(&(FOContext->FilterContextsMutex));

    return PerFOContext;
}

FsRtlRemovePerStreamContext()

PFSRTL_PER_STREAM_CONTEXT NTAPI FsRtlRemovePerStreamContext	(	IN PFSRTL_ADVANCED_FCB_HEADER	AdvFcbHeader,
		IN PVOID OwnerId	OPTIONAL,
		IN PVOID InstanceId	OPTIONAL
	)

Definition at line 312 of file filtrctx.c.

{
    PLIST_ENTRY NextEntry;
    PFSRTL_PER_STREAM_CONTEXT TmpPerStreamContext, PerStreamContext = NULL;

    if (!(AdvFcbHeader) || !(AdvFcbHeader->Flags2 & FSRTL_FLAG2_SUPPORTS_FILTER_CONTEXTS))
    {
        return NULL;
    }

    ExAcquireFastMutex(AdvFcbHeader->FastMutex);
    /* If list is empty, no need to browse it */
    if (!IsListEmpty(&(AdvFcbHeader->FilterContexts)))
    {
        for (NextEntry = AdvFcbHeader->FilterContexts.Flink;
             NextEntry != &(AdvFcbHeader->FilterContexts);
             NextEntry = NextEntry->Flink)
        {
            /* If we don't have any criteria for search, first entry will be enough */
            if (!OwnerId && !InstanceId)
            {
                PerStreamContext = (PFSRTL_PER_STREAM_CONTEXT)NextEntry;
                break;
            }
            /* Else, we've to find something that matches with the parameters. */
            else
            {
                TmpPerStreamContext = CONTAINING_RECORD(NextEntry, FSRTL_PER_STREAM_CONTEXT, Links);
                if ((InstanceId && TmpPerStreamContext->InstanceId == InstanceId && TmpPerStreamContext->OwnerId == OwnerId) ||
                    (OwnerId && TmpPerStreamContext->OwnerId == OwnerId))
                {
                    PerStreamContext = TmpPerStreamContext;
                    break;
                }
            }
        }

        /* Finally remove entry from list */
        if (PerStreamContext)
        {
            RemoveEntryList(&(PerStreamContext->Links));
        }
    }
    ExReleaseFastMutex(AdvFcbHeader->FastMutex);

    return PerStreamContext;

}

FsRtlTeardownPerStreamContexts()

VOID NTAPI FsRtlTeardownPerStreamContexts

(

IN PFSRTL_ADVANCED_FCB_HEADER

AdvFcbHeader

)

Definition at line 368 of file filtrctx.c.

{
    PLIST_ENTRY NextEntry;
    volatile BOOLEAN IsMutexLocked = FALSE;
    PFSRTL_PER_STREAM_CONTEXT PerStreamContext;

    _SEH2_TRY
    {
        /* Acquire mutex to deal with the list */
        ExAcquireFastMutex(AdvFcbHeader->FastMutex);
        IsMutexLocked = TRUE;

        /* While there are items... */
        while (!IsListEmpty(&(AdvFcbHeader->FilterContexts)))
        {
            /* ...remove one */
            NextEntry = RemoveHeadList(&(AdvFcbHeader->FilterContexts));
            PerStreamContext = CONTAINING_RECORD(NextEntry, FSRTL_PER_STREAM_CONTEXT, Links);

            /* Release mutex before calling callback */
            ExReleaseFastMutex(AdvFcbHeader->FastMutex);
            IsMutexLocked = FALSE;

            /* Call the callback */
            ASSERT(PerStreamContext->FreeCallback);
            (*PerStreamContext->FreeCallback)(PerStreamContext);

            /* Relock the list to continue */
            ExAcquireFastMutex(AdvFcbHeader->FastMutex);
            IsMutexLocked = TRUE;
        }
    }
    _SEH2_FINALLY
    {
        /* If mutex was locked, release */
        if (IsMutexLocked)
        {
            ExReleaseFastMutex(AdvFcbHeader->FastMutex);
        }
    }
    _SEH2_END;
}

Referenced by CdDeleteFcb(), Ext2FreeFcb(), FatDeleteFcb(), FatTearDownVcb(), and RxFreeFcbObject().